ConnectionRead (recv())

  • I have two web servers in my DMZ (One NT4 and on Win2K) that connect to a SQL 2000 server in the LAN. I have updated to MDAC 2.7.

    So far it is working quite well except that EVERY 10 minutes on the dot I get one or two of the following error messages and then everything works normally:

    [Microsoft][ODBC SQL Server Driver][TCP/IP sockets]ConnectionRead (recv())

    Traffic to all servers involved is VERY light right now, so there is no way the network is overloaded.

    The firewall logs claim that is is not blocking any traffic to or from the database server.

  • We've been having similar problems, getting this message:

    [DBNETLIB][ConnectionRead(recv()]

    And also [DBNETLIB][ConnectionOpen(connect()] SQL server does not exist or access is denied.

    We're not getting the problems as regularly as you are though.

    The following thread has more information in it:

    http://www.sqlservercentral.com/forum/topic.asp?TOPIC_ID=12410&FORUM_ID=20&CAT_ID=2&Topic_Title=SQL+server+does+not+exist+or+access+denied&Forum_Title=Connecting

    Are you using COM at all?


    Growing old is mandatory, growing up is optional

  • We are only using TCP/IP with and ODBC connection. SP3a on the sql server and Windows 2003 server.

    Last night I set up a countinuous ping from the database server to the web server and every 10 minutes the ping would fail once and then pick right up again.

    From my machine to the database server (which does not go through the firewall) I can ping all night without a failure. Pinging from my machine to the web server resulted in about 3 failures in 12 hours vs 64 for the database server to the web server.

    I have updated the network drivers on the database server.

    Looks like I will be making another call to the firewall guys. The fact that the problem is not random and occures at exactly 10 minute intervals leads me to believe that it is some sort of setting.

  • Problem Solved.

    After running a packet sniffer for a while I discovered that there was an ARP request for the IP of the database server right before the problem. So as it turns out there was a network camara sharing its IP address.

    The camara was on the same network segment so its ARP request was seen first by the web server, so the SQL traffic was directed to the camara until x ms later the ARP request from the database server came through the firewall and redirected the connection back to itself.

    Because of NAT neither machine realized there was an IP address conflict.

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